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Published on: March 20, 2021
Embryonic markers of cone differentiation
Helen M Rodgers1, Marycharmain Belcastro2, Maxim Sokolov3
1Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, WV; Neuroscience Graduate Program, West Virginia University School of Medicine, Morgantown, WV; Department of Otolaryngology, West Virginia University School of Medicine, Morgantown, WV.
Visual transduction proteins phosducin (Pdc) and cone transducin gamma (Gngt2) are expressed early in developing mouse cones. This occurs before opsin gene expression, suggesting a role beyond visual transduction during embryogenesis.
Area of Science:
- Developmental biology
- Neuroscience
- Molecular biology
Background:
- Photoreceptor cells, including cones and rods, develop in distinct phases during vertebrate retinogenesis.
- While cone formation begins during embryogenesis, their visual transduction machinery is not functional until the second postnatal week.
- Key proteins involved in cone visual transduction during early development remain largely uncharacterized.
Purpose of the Study:
- To characterize the expression of visual transduction proteins in mouse photoreceptors during embryogenesis.
- To investigate the temporal and spatial expression patterns of phosducin (Pdc) and cone transducin gamma (Gngt2) during early retinal development.
Main Methods:
- Utilized immunohistochemistry and quantitative reverse transcriptase-PCR (qPCR) on eye tissue from control and phosducin-null mice.
- Analyzed spatial and temporal expression of Pdc and Gngt2 proteins and transcripts at embryonic and early postnatal ages.
Main Results:
- Identified embryonic expression of phosducin and cone transducin gamma coinciding with early cone histogenesis.
- Phosducin protein detected at embryonic day (E)12.5, cone transducin gamma at E13.5, both in the outer neuroblastic layer.
- Pdc and Gngt2 mRNAs detected by E10.5, indicating early transcriptional activation.
Conclusions:
- Visual transduction proteins are expressed in developing cones early in embryogenesis, preceding opsin gene expression.
- The early expression suggests potential functions for these G-protein signaling components beyond mature visual transduction.
- This study provides insights into the molecular events governing early cone development and function.
